Laboratory experiments on the weathering of iron meteorites and carbonaceous chondrites by iron‐oxidizing bacteria

Abstract

Abstract-Batch culture experiments were performed to investigate the weathering of meteoritic material by iron-oxidizing bacteria. The aerobic, acidophilic iron oxidizer (A. ferrooxidans) was capable of oxidizing iron from both carbonaceous chondrites (Murchison and Cold Bokkeveld) and iron meteorites (York and Casas Grandes). Preliminary iron isotope results clearly show contrasted iron pathways during oxidation with and without bacteria suggesting that a biological role in meteorite weathering could be distinguished isotopically. Anaerobic iron-oxidizers growing under pH-neutral conditions oxidized iron from iron meteorites. These results show that rapid biologicallymediated alteration of extraterrestrial materials can occur in both aerobic and anaerobic environments. These results also demonstrate that iron can act as a source of energy for microorganisms from both iron and carbonaceous chondrites in aerobic and anaerobic conditions with implications for life on the early Earth and the possible use of microorganisms to extract minerals from asteroidal material.

Iron isotope fractionation during Fe(II) and Fe(III) adsorption on cyanobacteria

“…Iron has four stable isotopes ( 54 Fe, 56 Fe, 57 Fe, and 58 Fe), known to fractionate during abiotic and bacterially mediated processes in low temperature environments (e.g., Bullen et al 2001;Anbar 2004;Gronstal et al, 2009;Beard et al 2010). Numerous studies have investigated the isotopic effects during Fe interactions between aqueous and solids interfaces.…”

Effect of hot desert weathering on the bulk‐rock iron isotope composition of L6 and H5 ordinary chondrites

“…Recently, meteorite weathering experiments have confirmed the abundance of iron oxyhydroxides and sulfates in alteration products (Lee et al. 2006; Gronstal et al. 2009).…”

Determining the age and possibility for an extraterrestrial impact formation mechanism of the Ilumetsa structures (Estonia)

“…; Gronstal et al. ). All these factors would significantly limit the ability of a metal detector to pick up a signal of any potential meteorite.…”